Many batteries utilize cylindrical battery cells assembled in series and parallel to meet the current and/or voltage demands of the battery. The battery cells may be stacked and electrically connected to one another via bus bars. Such cylindrical type batteries may be used in hybrid electric vehicles (HEVs) and fully electric vehicles for propulsion.
However, the inventors herein have recognized potential issues with cylindrical type multi-cell batteries. As one example, due to the low packing density of the battery cells in cylindrical type batteries, the batteries may be bulky. As such, the packaging size of a vehicle may be increased to accommodate for the size of the battery. Further, the structural stability of the batteries may be reduced relative to batteries comprising rectangular battery cells, at least in part due to the shape of the cylindrical battery cells. Additionally, such cylindrical type batteries comprise complex electrical circuitry, and as such, diagnosing and correcting issues at a subassembly level may take a significant amount of time.
In one example, the issues described above may be addressed by a battery assembly comprising a cell group, the cell group comprising three cylindrical battery cells arranged in a triangular configuration, an electrical isolation spacer positioned between the three cylindrical battery cells and extending between ends of the battery cells, and a casing wrapped around the battery cells for restricting relative movement of the cells and spacer, the battery further comprising a housing for retaining the cell group.
In another example a battery may comprise a plurality of cylindrical cells, a primary sheath binding three of the plurality of cylindrical cells together to form a cell group, a secondary sheath binding two or more cell groups, a battery cell module comprising the secondary sheath and two or more cell groups, and a housing containing the battery cell module.
In yet another example, a vehicle battery may comprise two or more battery cell modules, each of the two or more battery cell modules comprising two or more cell groups, the two or more cell groups comprising three cylindrical battery cells and a primary sheath wrapped around the cells, two or more electrical isolation spacers positioned between the two or more cell groups, a secondary sheath wrapped around the two or more cell groups, bus bars electrically coupling the cylindrical battery cells of the two or more cell groups, and a voltage monitoring tab, electrically coupled to the bus bars for monitoring voltages of the cylindrical battery cells, an inter-module connector for electrically coupling the two or more battery cell modules, and a housing for retaining the two or more battery cell modules.
In this way, the packing density of a cylindrical type battery may be increased by wrapping the battery cells in groups of three with a sheath. Further, the packing density may be increased by stacking the groups to form cell modules, and then electrically coupling the cell modules via bus bars. By wrapping the cells in groups of three and physically binding them, the rigidity of the cell modules may be increased. Said another way, movement of the cylindrical cells relative to one another may be reduced.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.
Each of these figures is drawn approximately to scale and thus show relative sizing and positioning of components with respect to each other. In alternative embodiments, different relative sizing and/or positioning may be used, if desired.